#
# = ping.rb: Check a host for upness
#
# Author:: Yukihiro Matsumoto
# Documentation:: Konrad Meyer
#
# Performs the function of the basic network testing tool, ping.
# See: Ping.
#
require 'timeout'
require "socket"
#
# Ping contains routines to test for the reachability of remote hosts.
# Currently the only routine implemented is pingecho().
#
# Ping.pingecho uses a TCP echo (not an ICMP echo) to determine if the
# remote host is reachable. This is usually adequate to tell that a remote
# host is available to telnet, ftp, or ssh to.
#
# Warning: Ping.pingecho may block for a long time if DNS resolution is
# slow. Requiring 'resolv-replace' allows non-blocking name resolution.
#
# Usage:
#
# require 'ping'
#
# puts "'jimmy' is alive and kicking" if Ping.pingecho('jimmy', 10)
#
module Ping
#
# Return true if we can open a connection to the hostname or IP address
# +host+ on port +service+ (which defaults to the "echo" port) waiting up
# to +timeout+ seconds.
#
# Example:
#
# require 'ping'
#
# Ping.pingecho "google.com", 10, 80
#
def pingecho(host, timeout=5, service="echo")
begin
timeout(timeout) do
s = TCPSocket.new(host, service)
s.close
end
rescue Errno::ECONNREFUSED
return true
rescue Timeout::Error, StandardError
return false
end
return true
end
module_function :pingecho
end
if $0 == __FILE__
host = ARGV[0]
host ||= "localhost"
printf("%s alive? - %s\n", host, Ping::pingecho(host, 5))
end
|